Golden YaruIconButton test (#294)

NOTE: To update golden images, run:
```
flutter test --update-goldens
```

dart_test.yaml

@@ -0,0 +1,2 @@
+tags:
+  golden:

lib/src/controls/yaru_icon_button.dart

@@ -63,25 +63,25 @@ class YaruIconButton extends StatelessWidget {
       }),
       overlayColor: MaterialStateProperty.resolveWith((states) {
         if (states.contains(MaterialState.selected)) {
+          if (states.contains(MaterialState.pressed)) {
+            return colors.onSurface.withOpacity(0.12);
+          }
           if (states.contains(MaterialState.hovered)) {
             return colors.onSurface.withOpacity(0.08);
           }
           if (states.contains(MaterialState.focused)) {
             return colors.onSurface.withOpacity(0.12);
           }
-          if (states.contains(MaterialState.pressed)) {
-            return colors.onSurface.withOpacity(0.12);
-          }
+        }
+        if (states.contains(MaterialState.pressed)) {
+          return colors.onSurfaceVariant.withOpacity(0.12);
         }
         if (states.contains(MaterialState.hovered)) {
           return colors.onSurfaceVariant.withOpacity(0.08);
         }
         if (states.contains(MaterialState.focused)) {
           return colors.onSurfaceVariant.withOpacity(0.08);
         }
-        if (states.contains(MaterialState.pressed)) {
-          return colors.onSurfaceVariant.withOpacity(0.12);
-        }
         return null;
       }),
     );

pubspec.yaml

@@ -15,9 +15,11 @@ dependencies:
   yaru_icons: ^0.2.4
 
 dev_dependencies:
+  collection: ^1.16.0
   flutter_lints: ^1.0.0
   flutter_test:
     sdk: flutter
+  golden_toolkit: ^0.13.0
   test: ^1.21.4
 
 flutter:

test/controls/yaru_icon_button_test.dart

@@ -0,0 +1,91 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:yaru_icons/yaru_icons.dart';
+import 'package:yaru_widgets/yaru_widgets.dart';
+
+import '../yaru_golden_tester.dart';
+
+void main() {
+  testWidgets(
+    'golden images',
+    (tester) async {
+      final variant = goldenVariant.currentValue!;
+
+      // ensure traditional focus highlight
+      FocusManager.instance.highlightStrategy =
+          FocusHighlightStrategy.alwaysTraditional;
+
+      await tester.pumpScaffold(
+        YaruIconButton(
+          autofocus: variant.hasState(MaterialState.focused),
+          isSelected: variant.states[MaterialState.selected],
+          onPressed: variant.hasState(MaterialState.disabled) ? null : () {},
+          icon: const Icon(YaruIcons.star_filled),
+        ),
+        themeMode: variant.themeMode,
+        size: const Size(40, 40),
+      );
+      await tester.pumpAndSettle();
+
+      if (variant.hasState(MaterialState.pressed)) {
+        await tester.down(find.byType(YaruIconButton));
+        await tester.pumpAndSettle();
+      } else if (variant.hasState(MaterialState.hovered)) {
+        await tester.hover(find.byType(YaruIconButton));
+        await tester.pumpAndSettle();
+      }
+
+      await expectLater(
+        find.byType(YaruIconButton),
+        matchesGoldenFile('goldens/yaru_icon_button-${variant.label}.png'),
+      );
+    },
+    variant: goldenVariant,
+    tags: 'golden',
+  );
+}
+
+final goldenVariant = ValueVariant({
+  // normal (non-toggle) button
+  ...goldenThemeVariants('normal'),
+  ...goldenThemeVariants('disabled', {MaterialState.disabled: true}),
+  ...goldenThemeVariants('focused', {MaterialState.focused: true}),
+  ...goldenThemeVariants('hovered', {MaterialState.hovered: true}),
+  ...goldenThemeVariants('pressed', {MaterialState.pressed: true}),
+  // selected toggle button
+  ...goldenThemeVariants('selected', {MaterialState.selected: true}),
+  ...goldenThemeVariants('selected-disabled', {
+    MaterialState.selected: true,
+    MaterialState.disabled: true,
+  }),
+  ...goldenThemeVariants('selected-focused', {
+    MaterialState.selected: true,
+    MaterialState.focused: true,
+  }),
+  ...goldenThemeVariants('selected-hovered', {
+    MaterialState.selected: true,
+    MaterialState.hovered: true,
+  }),
+  ...goldenThemeVariants('selected-pressed', {
+    MaterialState.selected: true,
+    MaterialState.pressed: true,
+  }),
+  // unselected toggle button
+  ...goldenThemeVariants('unselected', {MaterialState.selected: false}),
+  ...goldenThemeVariants('unselected-disabled', {
+    MaterialState.selected: false,
+    MaterialState.disabled: true,
+  }),
+  ...goldenThemeVariants('unselected-focused', {
+    MaterialState.selected: false,
+    MaterialState.focused: true,
+  }),
+  ...goldenThemeVariants('unselected-hovered', {
+    MaterialState.selected: false,
+    MaterialState.hovered: true,
+  }),
+  ...goldenThemeVariants('unselected-pressed', {
+    MaterialState.selected: false,
+    MaterialState.pressed: true,
+  }),
+});

test/flutter_test_config.dart

@@ -0,0 +1,8 @@
+import 'dart:async';
+
+import 'package:golden_toolkit/golden_toolkit.dart';
+
+Future<void> testExecutable(FutureOr<void> Function() testMain) async {
+  await loadAppFonts();
+  return testMain();
+}

test/yaru_golden_tester.dart

@@ -0,0 +1,94 @@
+import 'package:collection/collection.dart';
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:yaru/yaru.dart';
+
+extension YaruGoldenTester on WidgetTester {
+  Future<void> pumpScaffold(
+    Widget widget, {
+    ThemeMode? themeMode,
+    ThemeData? theme,
+    ThemeData? darkTheme,
+    Size? size,
+  }) {
+    binding.window.devicePixelRatioTestValue = 1;
+    if (size != null) binding.window.physicalSizeTestValue = size;
+    return pumpWidget(
+      MaterialApp(
+        themeMode: themeMode,
+        theme: theme ?? yaruLight,
+        darkTheme: darkTheme ?? yaruDark,
+        home: Scaffold(
+          body: Center(child: widget),
+        ),
+      ),
+    );
+  }
+
+  Future<void> hover(Finder finder) async {
+    final gesture = await createGesture(kind: PointerDeviceKind.mouse);
+    await gesture.addPointer();
+    addTearDown(gesture.removePointer);
+    await gesture.moveTo(getCenter(finder));
+  }
+
+  Future<void> down(Finder finder) async {
+    final gesture = await createGesture(kind: PointerDeviceKind.mouse);
+    await gesture.addPointer();
+    addTearDown(gesture.removePointer);
+    await gesture.down(getCenter(finder));
+  }
+}
+
+@immutable
+class YaruGoldenVariant {
+  YaruGoldenVariant({
+    required String label,
+    required this.themeMode,
+    this.states = const {},
+  }) : label = '$label-${themeMode.name}';
+
+  final String label;
+  final ThemeMode themeMode;
+  final Map<MaterialState, bool> states;
+
+  bool hasState(MaterialState state) => states[state] == true;
+
+  @override
+  bool operator ==(Object other) {
+    if (identical(this, other)) return true;
+    final mapEquals = const MapEquality().equals;
+    return other is YaruGoldenVariant &&
+        other.label == label &&
+        other.themeMode == themeMode &&
+        mapEquals(other.states, states);
+  }
+
+  @override
+  int get hashCode {
+    final mapHash = const MapEquality().hash;
+    return Object.hash(label, themeMode, mapHash(states));
+  }
+
+  @override
+  String toString() => '$label: themeMode: $themeMode, states: $states';
+}
+
+List<YaruGoldenVariant> goldenThemeVariants(
+  String label, [
+  Map<MaterialState, bool> states = const {},
+]) {
+  return [
+    YaruGoldenVariant(
+      label: label,
+      themeMode: ThemeMode.light,
+      states: states,
+    ),
+    YaruGoldenVariant(
+      label: label,
+      themeMode: ThemeMode.dark,
+      states: states,
+    ),
+  ];
+}